George Allen of Old Dominion University operates a precision GPS receiver at Salters Creek in Newport News for a feasibility pilot project to test out using advanced geospatial technologies to build more accurate flood maps.- Original Credit: Tom Allen- Original Source: ODU

George Allen of Old Dominion University operates a precision GPS receiver at Salters Creek in Newport News for a feasibility pilot project to test out using advanced geospatial technologies to build more accurate flood maps.- Original Credit: Tom Allen- Original Source: ODU

Coastal geographer Tom Allen and drone pilot George McLeod were at Salters Creek in southeast Newport News flying a quadcopter to collect data when a resident brought them both down to earth.

Allen and McLeod were there to test the feasibility of using advanced technologies to capture high-resolution images to produce more accurate 3D maps and computer models of future flooding.

They hadn’t expected to speak with someone who actually lived in the neighborhood and whose home could be in the cross hairs of sea level rise.

Her name was Mamie, they recalled. She said she’d lived along Salters Creek “a long time” and had seen flooding worsen over the years.

“As scientists, we don’t always think about that right away,” said McLeod, assistant director of the Center for Geospatial and Visualization Computing at Old Dominion University in Norfolk.

“And her little visit to our field work brought home that there’s another way to look at these data. And sometimes it’s not positive, and sometimes we aren’t thinking about all the ramifications from a political or social angle that other people look at.”

Still, their small pilot project — unfunded, and more of a self-directed exploratory mission for the ODU researchers — could one day help the Salters Creek community and others like it.

For one thing, drones provide finer detail and more refined images than the more common yet more coarse versions currently crafted from laser pulses shot earthward from aircraft, called LIDAR technology.

With the use of geographic information systems software, or GIS, improved drone imagery can produce more accurate 3D surface maps. These could in turn bolster scientific and public confidence in computer models, including predictions of where the water will go in decades to come.

“We’re all living around the water — it’s one of the greatest assets here,” said Allen. “So, if we can have a better model, then we can predict where the marshes can go. And, as we’re forced to protect some areas, we can also build sea walls, hard infrastructures. We may also be able to conserve or even restore others.”

The researchers dreamed up their pilot project last summer and wrapped up the drone flights in the last few weeks.

They chose Salters Creek out of other areas throughout Hampton Roads because it happened to fit their very specific needs.

The creek sidewinds south through a low-lying community and into Peterson’s Yacht Basin before draining into the nexus of the mouth of the James River and the Chesapeake Bay.

Along the way, it curves around a mix of land uses — marshes and mud flats, streets and interstates, a cemetery, residential neighborhoods and commercial properties.

“It has people and infrastructure that could be in harm’s way,” Allen said.

It also isn’t constrained by Federal Aviation Administration rules the way so many local neighborhoods are because of their proximity to commercial airports and military bases. This gave researchers a freer hand to fly their drone.

And Salters Creek is recognized as flood-prone by the city, which already has sought federal and other funding to address water issues.

The pair used a quadcopter drone, roughly 10 pounds and 1 foot cubed. They flew only a few missions of about 20 minutes each to gather a vast portfolio of quality images. More flights weren’t needed to assess the creek environment, they said.

Besides, the more intense work lay in the painstaking planning before each flight and the painstaking analysis of the data afterward.

They used the drone images and GIS software — known collectively as geospatial technologies — to develop a more accurate baseline of what the area looks like on a typical non-flood day.

From that baseline, they can overlay computer simulations of sea level rise and storm surges not only under current conditions, but 30, 40 or 50 years out as rise accelerates.

While there are various projections of how high waters will get in coming decades, the researchers adopted the same projections as the Hampton Roads Planning Commission.

In a resolution last October, member localities voted to recognize sea level rise scenarios of 1.5 feet from 2018 to 2050, 3 feet from 2050 to 2080 and 4.5 feet from 2080 to 2100.

The planning commission decided that a standardized rate of projected rise helps in making land use and engineering decisions, and makes it easier for localities to work with state and federal agencies.

In part because of their eye-opening conversation with Mamie, but also because their data hasn’t been peer-reviewed yet, Allen and McLeod declined to share specific sea level rise projections for the neighborhood.

But they did find that flooding in that area “was not that extreme” under the 2050 and 2080 time frames as they might be elsewhere.

On the other hand, they did find spots of trouble.

“We’re talking about maybe putting a marsh in front of someone’s house where there’s a street (now),” said Allen.

But that, he said, was one potential future if nature were left to its own devices with no adaptations made, such as gray or green infrastructure. In this way, projections can be helpful in informing decision-making.

Allen and McLeod said their findings also are too raw to share with city officials.

“It’s very much an internal feasibility study,” Allen said. “But, now that we’ve kind of established its potential, it makes sense to engage communities.”

They’ve joined with the University of Virginia and other universities in seeking a National Science Foundation grant to create more drone maps and also look at community perceptions of hazards and policy changes. That effort might focus on neighborhoods in Hampton.

They’re also waiting to hear if the NASA Earth Science Disasters Program will fund expanding their work over a much broader area, including into North Carolina. That grant could be worth upwards of hundreds of thousands of dollars.

The Virginia Institute of Marine Science in Gloucester Point is among the academic partners on that potential effort. VIMS is affiliated with the College of William and Mary in Williamsburg.

“This will then provide maps and predictions of an alternative future where we (install) different types of infrastructure — nature-based or otherwise,” said Allen. “And it’s going to force our whole region to make some critical decisions. And do that block by block, neighborhood by neighborhood.”

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